Dispensing closures have been employed with a wide variety of products, including water, juices, condiments, and detergents. These dispensers allow the closure to be opened and closed without removing or separating any portion of the closure from the vessel.
There are several styles of dispensing closures currently commercially available. Pull/push, screw type and flip top are some common variations. These popular designs typically include a base and a spout assembled together. These designs rely upon multiple sealing surfaces to create an airtight closure for distribution and handling of the product. There are disadvantages associated with such designs. For example, upon dispensing the fluid from the vessel, a negative pressure condition or vacuum is created. Therefore, in order to dispense fluid, the vessel must be squeezed to force the fluid out. A portion of the contents exits the vessel upon squeezing, and upon release of the vessel, air re-enters to displace the fluid that has been dispensed. This cycle must be repeated numerous times to empty the contents of the vessel. Another disadvantage may be that the sealing assembly is not consistent because of manufacturing tolerances, slight burrs, and other manufacturing and assembly irregularities.
Bottling companies prefer to pressurize their products prior to shipment, which prevents damage to the product during transit. Additionally, pressurization would allow the bottler to reduce the wall thickness of the dispensing bottle, and rely on internal pressure to support the product during transit and handling. Current designs cannot hold adequate pressure to satisfactorily accomplish these needs. In addition, carbonated beverages and solutions cannot be marketed in these closures, because they would rapidly lose their carbonation and be rendered useless to the consumer.